Study of the influence of the porosity in ZnO samples applied to Advanced Oxidation Processes for water depollution

Reference	Presenter	Authors (Institution)	Abstract
06-032	Felipe de Paula Faria	Faria, F.d.(Universidade Federal de Alfenas); Storion, A.G.(Universidade Federal de Alfenas); Giraldi, T.R.(Universidade Federal de Alfenas); Roveri, C.D.(Universidade Federal de Alfenas); Maestrelli, S.C.(Universidade Federal de Alfenas-campus de Poços de Caldas);	The treatment and reuse of hydric resources has become a topic increasingly investigated by the scientific community. The traditional processes of water treatment have been proved insufficient and scarcely efficient, which gives room for the use of Advanced Oxidative Processes (AOPs). These methods are based on the activation, through radiation, of a semiconductor so that electronic transitions occur between valence and conduction bands, generating oxidant and reducer sites capable of triggering mineralization reactions of polluting compounds. Literature has many works which involve the use of different oxides, highlighting ZnO for photocatalytic evaluation. However, researches on the use of consolidated pieces for photocatalytic purpose have been poorly explored; powders of films are normally investigated. In this sense, it is extremely important that the finished product (piece) presents high porosity, in a way there is light penetration, promoting photocatalysis; it also must have mechanical resistance to be routinely used without premature rupture. In this paper it was investigated the effect of compaction pressure and sintering conditions in obtaining porous ceramics from Zinc Oxid. It was also evaluated their mechanical resistance and photocatalytic properties. The best results were obtained for the pieces sintered at 800°C for 2 hours, with porosity levels around 49%. For the pieces sintered at 1000°C for 2 hours, the decay of porosity (around 18%), although increases significantly mechanical resistance, compromises the photocatalytic properties of the final pieces, evidencing the strong influence of porosity. The authors thank the financial support from CNPq and FAPEMIG.
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